A. Fil D. Moulton B. Dudson B. Lipschultz K. Verhaegh O. Février O. Myatra C. Theiler M. Wensing EUROfusion MST1 teams the TCV team
In ITER and DEMO, achieving detachment at lower densities would allow to reduce the amount of impurity seeded and to improve confinement by running at lower separatrix densities. Analytic models predict that a increase of total flux expansion would allow such a reduction in upstream density at detachment. However, both experiments and modelling …
Preprint PublishedM. Carr A. Meakins S. Silburn J. Karhunen M. Bernert C. Bowman A. Callarelli P. Carvalho C. Giroud J. Harrison S. Henderson A. Huber B. Lipschultz T. Lunt D. Moulton F. Reimold ASDEX Upgrade team JET contributors MAST-Upgrade team the EUROfusion MST1 Team
Ray-tracing techniques are applied to divertor filtered imaging, a diagnostic that has long been plagued by polluting reflected light features in metal walled fusion machines. A physically realistic surface reflection model is developed from a Cook-Torrence microfacet BRDF model. Camera calibration images of in-vessel point lights at JET are use…
Preprint PublishedB D Dudson J Allen T Body B Chapman C Lau L Townley D Moulton J Harrison B Lipschultz
A new 1D divertor plasma code, SD1D, has been used to examine the role of recombination, radiation, and momentum exchange in detachment. Neither momentum or power losses by themselves are found to be sufficient to produce target ion flux rollover in detachment; radiative power losses are required to a) limit and reduce the ionization source and …
Preprint PublishedD. Moulton G. Corrigan J.R. Harrison B. Lipschultz JET Contributors
This paper further analyses the EDGE2D-EIRENE simulations presented by [Chankin et al (2017 Nucl. Mater. Energy 12 273], of L-mode JET plasmas in vertical-vertical (VV) and vertical-horizontal (VH) divertor configurations. As expected, the simulated outer divertor ionisation source peaks near the separatrix in VV …
Preprint PublishedN. R. Walkden A. Wynn F. Militello B. Lipschultz G. Matthews C.Guillemaut J. Harrison D. Moulton JET Contributors
This paper presents the use of a novel modelling technique based around intermittent transport due to filament motion, to interpret experimental profile and fluctuation data in the scrape-off layer (SOL) of JET during the onset and evolution of a density profile shoulder. Three cases are studied at different points in a density ramp experiment wher…
Preprint PublishedN.R. Walkden A. Wynn F. Militello B. Lipschultz G. Matthews C.Guillemaut J. Harrison D. Moulton JET Contributors
Statistical analysis of the ion flux to the JET outer-wall is conducted in outer-wall limiter mounted Langmuir probe (OLP) time-series across a wide range of plasma current and line-averaged density during Ohmically heated horizontal target L-mode plasmas. The mean, _, and the standard deviation, _, of the ion-saturation current measured by the OLP…
Preprint PublishedD. Moulton J. Harrison B. Lipschultz D. Coster
We show that a central characteristic of Super-X divertors, parallel area expansion fR (de ned as the ratio of the elementary area normal to the magnetic field at the target to that at the X-point, also known as total flux expansion), significantly changes the characteristics of the target plasma for fixed upstream conditions. To isolate the effect…
Preprint PublishedW. Fundamenski F. Militello D. Moulton D.C. Mcdonald
A new model of the L–H transition in tokamaks is proposed, based on the criterion that the transition occurs when plasma turbulence and shear Alfvén waves compete in the vicinity of the last-closed flux surface. The model is used to predict the scaling of the H-mode access power, PL–H, with magnetic and plasma variables. The predictio…
PublishedW.Fundamenski T.Eich D.Moulton F.Militello C.Lowry G.Maddison E.Havlickova D.Ward R.Kemp M.Wischmeier D.C.Mcdonald
Recent infra-red measurements of divertor power loads on JET and AUG [1], revealed that the inter-ELM power width at the outer mid-plane in attached ELMy H-modes does not exhibit any noticeable scaling with machine size [1]. Making use of these results to calculate the effective radial heat diffusivity, and then including this in parametrized expre…
PublishedE Havlicková W Fundamenski D Tskhakaya G Manfredi D Moulton
Parallel transport associated with Type I ELM filaments in the scrape-off layer (SOL) is studied by means of three computational approaches – fluid, Vlasov and particle-in-cell (PIC). These techniques are benchmarked for convective transients by analyzing power fluxes at the target. In spite of kinetic effects due to fast electrons which are not …
Published